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Lung Dissection Lesson

Lung Dissection Lesson

Welcome to our Lung Dissection Lesson aimed at GCSE students.

We have a lung dissection video demonstrating the methodology of the classroom dissection of a pig’s lung.  We have included a lesson plan and risk assessments that can be downloaded or simply reviewed here.

We hope to guide pupils through discovering as much as they can from the lungs!

Aim: To explain how the structure of the lungs is related to their function

GCSE Biology

Methodology:

  • Place pluck on dissection board and lift to see all structures. Some of the listed structures may not be present in your sample depending on your order.
  • Structures: Larynx, Trachea, Oesophagus, Carotid arteries, Lungs, Diaphragm, Heart.
  • Arrange the lungs so that the larynx end of the trachea is closest to Put on your eye protection and use scissors to cut through the cartilage of the larynx from the epiglottis end.
  • Examine the vocal folds/cords in the larynx.
  • Cut along the trachea towards the lungs and look for the C- shaped rings of cartilage as you cut through them.
  • Look at the lining of the trachea. It contains goblet cells and ciliated cells.
  • Change the line of your cut so that you cut along a section of trachea without cutting through cartilage. This is where the oesophagus can bulge into the trachea when a food bolus is being swallowed.
  • Look at a small bronchus that branches into the uppermost lobe of the lung
  • Cut into a main bronchus.
  • Continue cutting along it and towards the bottom of the lung.
  • Identify different levels of bronchi are lined with cartilage.
  • Observe the spongy nature of the lung tissue. This will contain the bronchioles, alveoli and pulmonary blood vessels.
  • When you cut into it you can see that it is permeated with air-filled tubes and blood vessels.
  • Place a sponge tissue sample in water to observe it float.

 

Teaching Notes:

 The lungs are a pair of large, spongy organs for gas exchange between blood and the air.

Observations to point out:

  • A flap-like epiglottis closes the opening to the larynx during swallowing
  • The two lungs are subdivided into lobes and are covered by the inner (visceral) pleural membrane. The cuts in the lungs are for inspection at the abattoir
  • The trachea is a flexible tube that is held open by incomplete rings of cartilage so oesophagus can bulge into the trachea when a food bolus is being swallowed.
  • It links the mouth with the lungs lining of the trachea. It contains goblet cells and ciliated cells that secrete and move mucus to trap small foreign objects.
  • Oesophagus is a muscular tube that is attached to the dorsal side of the trachea.
  • Surfaces of the lung are specialised for exchanging materials. The effectiveness of an exchange surface is increased by:

– large surface area provided by a large number of alveoli air sacs.

– a membrane that is thin, to provide a short diffusion path.

– having an efficient blood supply provided by a capillary network.

– ventilation mechanism.

  • The lung tissue floats in water because the air in the alveoli air sacs gives the lung tissue a low density.
  • Samples for Schools Pluck
  • Dissection board
  • Scalpel
  • Scissors
  • Eye Protection
  • Paper towel

AQA: Topic 4.1.3.1, 4.2.2.2, 4.2.2.4 and 4.2.2.6

Students should know the structure and functioning of the human heart and lungs, including how lungs are adapted for gaseous exchange. Knowledge of the lungs is restricted to the trachea, bronchi, alveoli and the capillary network surrounding the alveoli.

Edexcel: Topic 8.3

Students should explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries

Eduqas: Topic 2.2

Students should describe the human circulatory system as a double circulatory system and its relationship with the gaseous exchange system.

OCR 21st Century: Topic B5.1

Students should describe the human circulatory system, including its relationships with the gaseous exchange system, the digestive system and the excretory system

Students should explain the need for exchange surfaces and a transport system in mul cellular organisms in terms of surface area/volume ratio

OCR Gateway: Topic 2.2

Students should explain the need for exchange surfaces and a transport system in multicellular organisms in terms of surface area/volume ratio.